Question

I am working on a survey application in ruby on rails and on the results page I want to let users filter the answers by a bunch of demographic questions I asked at the start of the survey.

For example I asked users what their gender and career was. So I was thinking of having dropdowns for gender and career. Both dropdowns would default to all but if a user selected female and marketer then my results page would so only answers from female marketers.

I think the right way of doing this is to use named_scopes where I have a named_scope for every one of my demographic questions, in this example gender and career, which would take in a sanitized value from the dropdown to use at the conditional but i’m unsure on how to dynamically create the named_scope chain since I have like 5 demographic questions and presumably some of them are going to be set to all.

Answer 1

You can chain named scopes together:

def index
  @results = Results.scoped
  @results = @results.gender(params[:gender]) unless params[:gender].blank?
  @results = @results.career(params[:career]) unless params[:career].blank?
end

I prefer however to use the has_scope gem:

has_scope :gender
has_scope :career

def index
  @results = apply_scopes(Results).all
end

If you use has_scope with inherited_resources, you don’t even need to define the index action.